1. Field of the Invention
The present invention relates to an occupant restraint system in which a side airbag is disposed in a folded state along an upper edge of a door opening of a vehicle body, and the airbag is inflatable by a gas, generated by an inflator, when the vehicle is involved in a collision. Upon activation thereof, the airbag is deployed in a curtain shape along the inner face of a side of an occupant compartment.
2. Description of the Related Art
Such an occupant restraint system is known in, for example, Japanese Patent Application Laid-open Nos. 2000-33847 and 11-235965. The airbag of this type of occupant restraint system is folded in a zigzag manner along fold lines extending in the longitudinal direction and designed so that it deploys when a gas is supplied to a plurality of cells extending downward from an upper communicating passage extending to an inflator.
The cells of the airbag are defined by sewing two fabrics superimposed one on top of the other, the parts interposed between adjoining lines of stitching forming cells, which are inflated by the gas that flows in. As a result, the cell end parts, formed by the point where the stitching stops, cannot be inflated sufficiently since the two sheets of fabric are united by sewing, and there is a possibility that these parts might have an insufficient impact-absorbing effect.
Furthermore, if the upper ends of the cells extending to the upper communicating passage of the airbag are aligned along one of the fold lines, in some cases the pressure of the gas inflating the airbag might be distributed equally to all of the cells, resulting in individual cells becoming bent in two at the center in the vertical direction, and preventing smooth deployment.